JP2021133546A - Thermal transfer sheet, and combination of the thermal transfer sheet and intermediate transfer medium - Google Patents

Abstract

To provide a thermal transfer sheet which can effectively suppress occurrence of reverse transcription even when peeling between a thermal transfer sheet and an intermediate transfer medium in primary transfer is performed at low temperature.SOLUTION: A thermal transfer sheet 10 includes a first base material 11, a release layer 12, and a transfer layer 13 including at least a melt transfer type coloring material layer 14. The release layer contains at least two urethane resins and at least one acetal resin, and a peeling force when heated of the transfer layer with a width of 25 mm is 0.4 N or more and 0.8 N or less.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a thermal transfer sheet and a combination of the thermal transfer sheet and an intermediate transfer medium.

Conventionally, various thermal transfer recording methods are known. For example, a thermal transfer sheet having a transfer layer having a melt transfer type color material layer on a base material and a transfer target are superposed, and then passed between a thermal head and a platen roller provided in the thermal transfer printer, and the thermal is formed. A thermal melt transfer method is known in which a transfer layer is transferred onto an image to be transferred to form an image by heating a thermal transfer sheet with a head to produce a printed matter.

Further, it is widely practiced to manufacture a printed matter by using such a thermal transfer sheet in combination with an intermediate transfer medium.
Specifically, first, the thermal transfer sheet and the intermediate transfer medium are superposed, and the thermal transfer sheet is heated to form an image on the receiving layer provided in the intermediate transfer medium (primary transfer). Next, the intermediate transfer medium and the transfer target are superposed, and the intermediate transfer medium is heated to transfer (secondary transfer) the receiving layer on which the image is formed onto the transfer target to produce a printed matter. do.

In the production of the printed matter using the above-mentioned thermal transfer sheet and intermediate transfer medium, the transfer layer of the thermal transfer sheet is formed without the receiving layer included in the intermediate transfer medium being peeled off to the thermal transfer sheet side (hereinafter referred to as reverse transfer). It is required to be transcribed on the receiving layer. If the thermal transfer sheet and the intermediate transfer medium are peeled off at a low temperature of about 60 ° C. during the primary transfer, the possibility of reverse transfer increasing increases, which is a particular problem.

An object of the present disclosure is that even when the thermal transfer sheet and the intermediate transfer medium are peeled off at a low temperature in the primary transfer, the occurrence of reverse transcription can be effectively suppressed (hereinafter referred to as reverse transcription inhibitory property). To provide a sheet.
Another object of the present disclosure is to provide a combination of the thermal transfer sheet and an intermediate transfer medium.

The thermal transfer sheet of the present disclosure includes a first base material, a release layer, and a transfer layer including at least a melt transfer type color material layer.
The release layer contains at least two urethane resins and at least one acetal resin.
The thermal peeling force of the 25 mm wide transfer layer is 0.4 N or more and 0.8 N or less.

The combination of the thermal transfer sheet and the intermediate transfer medium of the present disclosure includes the thermal transfer sheet, an intermediate transfer medium including the second base material, and a receiving layer.

According to the present disclosure, it is possible to provide a thermal transfer sheet having a high reverse transcription inhibitory property. Further, according to the present disclosure, it is possible to provide a combination of the thermal transfer sheet and an intermediate transfer medium.

It is the schematic sectional drawing which shows one Embodiment of the thermal transfer sheet of this disclosure. It is the schematic sectional drawing which shows one Embodiment of the thermal transfer sheet of this disclosure. It is the schematic sectional drawing which shows one Embodiment of the thermal transfer sheet of this disclosure. It is schematic cross-sectional view which shows one Embodiment of the combination of the thermal transfer sheet of this disclosure and an intermediate transfer medium. It is a front view which shows the pattern image A formed on the receiving layer provided with the intermediate transfer medium in an Example. It is a partially enlarged view of the pattern image A of FIG.

(Thermal transfer sheet)
As shown in FIG. 1, the thermal transfer sheet 10 according to the present disclosure includes a first base material 11, a release layer 12, and a transfer layer 13. The transfer layer 13 includes at least a melt transfer type color material layer 14.
In one embodiment, as shown in FIG. 2, the transfer layer 13 includes a release layer 15 under the melt transfer type color material layer 14.
In one embodiment, as shown in FIG. 3, the thermal transfer sheet 10 includes a sublimation transfer type color material layer 16 so as to be surface-sequential with the transfer layer 12. Further, in one embodiment, the thermal transfer sheet 10 includes a primer layer between the first base material and the sublimation transfer type color material layer 16 (not shown).
In one embodiment, the thermal transfer sheet 10 includes a back surface layer 17 on a surface of the first base material 11 opposite to the surface on which the transfer layer 13 is provided.
Hereinafter, each layer included in the thermal transfer sheet of the present disclosure will be described.

(Base material)
The base material can be used without particular limitation as long as it has heat resistance to the heat energy applied during thermal transfer, and has mechanical strength and solvent resistance that can support the transfer layer and the like provided on the base material.

As the base material, a film composed of a resin material (hereinafter, simply referred to as "resin film") can be used. For example, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene methylene terephthalate, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, nylon. Polyethylene such as 6 and nylon 6,6, polyolefins such as polyethylene (PE), polypropylene (PP) and polymethylpentene, polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymer and Vinyl resins such as polyvinylpyrrolidone (PVP), vinyl acetal resins such as polyvinylacetacetal and polyvinylbutyral, (meth) acrylic resins such as polyacrylate and polymethacrylate, imide resins such as polyimide and polyetherimide, cellophane, cellulose acetate, etc. Examples thereof include cellulose resins such as nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB), styrene resins such as polystyrene (PS), polycarbonates, and ionomer resins.
Among the above-mentioned resin materials, polyester is preferable, PET or PEN is more preferable, and PET is particularly preferable, from the viewpoint of heat resistance and mechanical strength.

Further, the above-mentioned laminated body of the resin film can also be used as a base material. The laminate of the resin film can be produced by using a dry lamination method, a wet lamination method, an extraction method, or the like.

When the base material is a resin film, the resin film may be a stretched film or an unstretched film, but from the viewpoint of strength, a stretched film stretched in the uniaxial direction or the biaxial direction is used. It is preferable to use it.

The thickness of the base material is preferably 3.0 μm or more and 25.0 μm or less. As a result, the mechanical strength of the base material and the transfer of thermal energy during thermal transfer can be improved.

(Release layer)
The release layer contains at least two types of urethane resin and at least one type of acetal resin.
In the present disclosure, it means a resin having a urethane bond, and for example, a urethane resin can be obtained by reacting a polyol compound with an isocyanate compound.
Examples of the polyol include polyethylene glycol, polypropylene glycol, acrylic polyol, polyester polyol, polyether polyol, polycarbonate polyol, polyurethane polyol and the like. Examples of the isocyanate compound include 2,4-tolylene diisocyanate, xylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated diphenylmethane diisocyanate. And so on.
In the present disclosure, the acetal resin means a resin obtained by acetalizing an alcohol such as polyvinyl alcohol with an aldehyde.
Examples of the aldehyde include propionaldehyde, n-butylaldehyde, isobutylaldehyde, n-barrel aldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, and formaldehyde. , Acetaldehyde, benzaldehyde and the like.

The release layer contains a high Tg urethane resin and a low Tg urethane resin. Thereby, the reverse transcription inhibitory property can be further improved. In addition, it is possible to effectively suppress the occurrence of blurring and blurring in the image formed by the primary transfer of the transfer layer (hereinafter referred to as transferability).
The glass transition temperature (Tg) of the high Tg urethane resin is 50 ° C. or higher, and the glass transition temperature of the low Tg urethane resin is 10 ° C. or lower.
It is preferable that the glass transition temperature (Tg) of the high Tg urethane resin is 50 ° C. or higher and 110 ° C. or lower, and the glass transition temperature (Tg) of the low Tg urethane resin is Tg-50 ° C. or higher and 10 ° C. or lower.
The Tg of the high Tg urethane resin is more preferably 70 ° C. or higher and 100 ° C. or lower.
The Tg of the low Tg urethane resin is more preferably −40 ° C. or higher and 0 ° C. or lower.
In the present disclosure, Tg is a value obtained by DSC (Differential Scanning Calorimetry) in accordance with JIS K 7121.

When the release layer contains a high Tg urethane resin and a low Tg urethane resin, the content ratio (high Tg urethane resin / low Tg urethane resin) is preferably 5/30 or more and 30/5 or less on a mass basis. More preferably, it is 5/25 or more and 15/20 or less. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.

The content of the urethane resin in the release layer is preferably 10% by mass or more and 45% by mass or less, and more preferably 15% by mass or more and 40% by mass or less. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.
When the release layer contains Tg of a high Tg urethane resin and a low Tg urethane resin, the content of the high Tg urethane resin in the release layer is preferably 5% by mass or more and 35% by mass or less, and 10% by mass or more and 30% by mass. % Or less is more preferable. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.
The content of the low Tg urethane resin in the release layer is preferably 3% by mass or more and 35% by mass or less, and more preferably 5% by mass or more and 25% by mass or less. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.

The Tg of the acetal resin is preferably 60 ° C. or higher and 120 ° C. or lower, and more preferably 80 ° C. or higher and 120 ° C. or lower. Thereby, the transferability can be further improved.

The content of the acetal resin in the release layer is preferably 55% by mass or more and 90% by mass or less, and more preferably 60% by mass or more and 85% by mass or less. Thereby, the transferability can be further improved.

In one embodiment, the release layer comprises at least one release material. Examples thereof include fluorine compounds, phosphoric acid ester compounds, silicone oils and higher fatty acid amide compounds, and waxes such as metal soaps and paraffin waxes.
Examples of the silicone oil include straight silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carboxy-modified silicone oil, (meth) acrylic-modified silicone oil, and mercapto-modified silicone oil. Examples thereof include modified silicone oils such as carbinol-modified silicone oil, fluorine-modified silicone oil, methylstyryl-modified silicone oil, and polyether-modified silicone oil. The modified silicone oil includes a single-ended type, a double-ended type, and a side chain single-ended type.

The release layer may contain a resin material other than urethane resin and acetal resin. For example, polyester, polyamide, polyolefin, vinyl resin, cellulose resin, styrene resin, polycarbonate, ionomer resin and the like can be mentioned.

The release layer may contain additives. Examples thereof include fillers, plastics, antistatic materials, ultraviolet absorbers, organic particles, inorganic particles, mold release materials and dispersants. ..

The thickness of the release layer is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.3 μm or more and 2 μm or less. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.

For the release layer, the above material is dispersed in water or a suitable solvent, or the material is dissolved in water or a suitable solvent to prepare a coating liquid, which is applied onto the first substrate to form a coating film. It can be formed by forming and drying it. As the coating means, known means such as a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, a bar coating method or a rod coating method can be used.

(Transfer layer)
The transfer layer includes at least a melt transfer type color material layer. Further, in one embodiment, the transfer layer includes a release layer under the melt transfer type coloring material layer.

In the thermal transfer sheet of the present disclosure, the thermal peeling force of the transfer layer having a width of 25 mm is 0.4 N or more and 0.8 N or less. Thereby, the reverse transcription inhibitory property can be effectively improved.
The thermal peeling force of the transfer layer is more preferably 0.4 N or more and 0.6 N or less.
In the present disclosure, the thermal peeling force of the transfer layer is measured as follows.
First, a thermal transfer sheet and a polyvinyl chloride (PVC) card (manufactured by Dai Nippon Printing Co., Ltd., width 50 mm x length 70 mm) are prepared, and the transfer layer of the thermal transfer sheet and the PVC card are opposed to each other. Printing is performed using a test printer to obtain a laminate in which the thermal transfer sheet and PVC are in close contact with each other.
Next, the laminate is cut into a width of 25 mm to prepare a peeling force measurement sample having a width of 25 mm and a length of 70 mm.
A peeling tester (VPA-3 manufactured by Kyowa Interface Science Co., Ltd.) is prepared, and the above-mentioned peeling force measurement sample is placed on the stage provided in the peeling tester so that the transferee side is in contact with the stage.
Set the peeling tester as follows and let it stand for 3 minutes.
Next, the base material of the thermal transfer sheet is peeled off, and the peeling force between the base material and the transfer layer is measured.
(Test printer)
-Thermal head: Kyocera Corporation, KEE-57-12GAN2-STA
-Average resistance value of heating element: 3303Ω
-Main scanning direction resolution: 300 dpi (dot per inch)
-Sub-scanning direction resolution: 300 dpi
・ Printing voltage: 18V
-Line speed: 2.0 msec. / Line
-Printing start temperature: 35 ° C
-Pulse duty ratio: 85%
-Print image: Solid black image (0/255 gradation)

(Peeling tester conditions)
・ Stage temperature: 60 ° C
・ Peeling angle: 90 °
・ Peeling speed: 2000 mm / min

(Melting transfer type color material layer)
The melt transfer type color material layer contains at least one color material, which may be a pigment or a dye. For example, carbon black, acetylene black, lamp black, black smoke, iron black, aniline black, silica, calcium carbonate, titanium oxide, cadmium red, cadmopone red, chrome red, vermilion, red iron oxide, azo pigments, alizarin lake, quinacridone, Cochineal Lake Perylene, Yellow Oaker, Aureolin, Cadmium Yellow, Cadmium Orange, Chrome Yellow, Zink Yellow, Naples Yellow, Nickel Yellow, Azo Pigments, Greenish Yellow, Ultramarine, Rocks Blue, Cobalt, Phthalocyanin, Anthracinone, Indicoid, Examples thereof include cinnabar green, cadmium green, chrome green, phthalocyanine, azomethine, perylene and aluminum pigments.

The content of the coloring material in the melt transfer type coloring material layer is preferably 10% by mass or more and 50% by mass or less, and more preferably 20% by mass or more and 45% by mass or less. Thereby, the density of the formed image can be improved.

In one embodiment, the melt transfer type colorant layer comprises at least one resin material. For example, polyester, polyamide, polyolefin, vinyl resin, vinyl acetal resin, (meth) acrylic resin, cellulose resin, styrene resin, polycarbonate, butyral resin, phenoxy resin, ionomer resin and the like can be mentioned.
Among these, a vinyl resin is preferable, and a vinyl chloride-vinyl acetate copolymer is particularly preferable, from the viewpoint of adhesion to the receiving layer provided in the intermediate transfer medium described later.

The content of the resin material in the melt transfer type color material layer is preferably 20% by mass or more and 75% by mass or less, and more preferably 30% by mass or more and 60% by mass or less. As a result, the adhesion to the receiving layer of the intermediate transfer medium described later can be further improved.

The melt transfer type color material layer may contain the above-mentioned additive.

The thickness of the melt transfer type color material layer is, for example, 0.3 μm or more and 5 μm or less.

In the melt transfer type coloring material layer, the above-mentioned material is dispersed in water or a suitable solvent, or the above-mentioned material is dissolved in water or a suitable solvent to prepare a coating liquid, and a release layer is prepared by the above-mentioned coating means. It can be formed by applying it on an or the like to form a coating film and drying it.

(Release layer)
In one embodiment, the transfer layer included in the thermal transfer sheet includes a release layer under the melt transfer type coloring material layer.

The release layer contains at least one resin material. For example, polyester, polyamide, polyolefin, vinyl resin, (meth) acrylic resin, imide resin, cellulose resin, styrene resin, polycarbonate, ionomer resin and the like can be mentioned.
Among these, (meth) acrylic resin or vinyl resin is preferable, and it is more preferable to contain both of them. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.
Further, among the vinyl resins, a vinyl chloride-vinyl acetate copolymer is more preferable.

The content of the resin material in the release layer is preferably 80% by mass or more and 99.9% by mass or less, and more preferably 90% by mass or more and 99.5% by mass or less. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.

In one embodiment, the release layer comprises the release material. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved. Among the above, silicone oil is preferable.

The content of the release material in the release layer is preferably 0.1% by mass or more and 20% by mass or less, and more preferably 0.5% by mass or more and 10% by mass or less. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.

The release layer may contain the above-mentioned additive.

The thickness of the release layer is preferably 0.1 μm or more and 3 μm or less, and more preferably 0.3 μm or more and 1.5 μm or less. Thereby, the reverse transcription inhibitory property and the transfer property can be further improved.

In the release layer, the material is dispersed in water or a suitable solvent, or the material is dissolved in water or a suitable solvent to prepare a coating liquid, which is applied onto the release layer by the coating means. It can be formed by forming a coating film and drying it.

(Sublimation transfer type color material layer)
In one embodiment, the heat transfer sheet of the present disclosure includes a sublimation transfer type color material layer on a first base material so as to be surface-sequential with the transfer layer. A plurality of sublimation transfer type color material layers may be provided.

The sublimation transfer type color material layer contains at least one sublimation dye. For example, diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolone dyes, methine dyes, indian aniline dyes, acetophenone azomethine dyes, pyrazoloazomethine dyes, xanthene dyes, oxazine dyes, thiazine dyes, azine dyes, acrydin dyes. , Azo dyes, spiropyran dyes, indolinospiropirane dyes, fluorane dyes, naphthoquinone dyes, anthraquinone dyes, quinophthalone dyes and the like.

In one embodiment, the sublimation transfer type color material layer contains at least one resin material. For example, (meth) acrylic resin, polyurethane, acetal resin, polyamide, polyester, melamine resin, polyol resin, cellulose resin, silicone resin and the like can be mentioned.

In one embodiment, the sublimation transfer type color material layer includes the above-mentioned mold release material. As a result, it is possible to prevent fusion between the receiving layer provided in the intermediate transfer medium described later and the sublimation transfer type coloring material layer at the time of image formation.

The content of the release material in the sublimation transfer type coloring material layer is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.05% by mass or more and 0.5% by mass or less. This makes it possible to further prevent fusion between the receiving layer and the sublimation transfer type coloring material layer provided in the intermediate transfer medium described later at the time of image formation.

The sublimation transfer type coloring material layer may contain the above-mentioned additive.

In the sublimation transfer type coloring material layer, the above-mentioned material is dispersed in water or a suitable solvent, or the above-mentioned material is dissolved in water or a suitable solvent to prepare a coating liquid, and the first group is prepared by the above-mentioned coating means. It can be formed by applying it on a material or the like to form a coating film and drying it.

(Primer layer)
In one embodiment, the thermal transfer sheet includes a primer layer between the first substrate and the sublimation transfer type color material layer.

In one embodiment, the primer layer comprises at least one resin material. For example, polyester, vinyl resin, polyurethane, (meth) acrylic resin, polyamide, polyether, styrene resin, cellulose resin and the like can be mentioned.
Moreover, the primer layer may contain the above-mentioned additive.

The thickness of the primer layer is, for example, 0.05 μm or more and 2.0 μm or less.

In the primer layer, the material is dispersed in water or a suitable solvent, or the material is dissolved in water or a suitable solvent to prepare a coating liquid, which is applied onto the substrate by the coating means. It can be formed by forming a coating film and drying it.

(Back layer)
In one embodiment, the thermal transfer sheet comprises a back layer on a surface opposite to the surface on which the transfer layer of the first substrate is provided. This makes it possible to prevent sticking and wrinkles due to heating during thermal transfer.

In one embodiment, the back layer comprises at least one resin material. For example, vinyl resin, polyester, polyamide, polyolefin, (meth) acrylic resin, polyolefin, polyurethane, cellulose resin, phenol resin and the like can be mentioned.

In one embodiment, the back layer comprises at least one isocyanate compound. For example, xylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate and the like can be mentioned.

The back layer may contain the above-mentioned mold release material and additive material.

The thickness of the back layer is, for example, 0.3 μm or more and 3.0 μm or less.

In the back layer, the material is dispersed in water or a suitable solvent, or the material is dissolved in water or a suitable solvent to prepare a coating liquid, which is applied onto the first substrate by the coating means. To form a coating film, which can be dried.

(Combination of thermal transfer sheet and intermediate transfer medium)
The combination of the thermal transfer sheet and the intermediate transfer medium according to the present disclosure is as shown in FIG.
A thermal transfer sheet 10 including at least the above-mentioned first base material 11, a release layer 12, and a transfer layer 13.
An intermediate transfer medium 20 including a second base material 21 and a receiving layer 22 is provided.
In one embodiment, the intermediate transfer medium 20 includes a release layer between the second substrate 21 and the receiving layer 22 (not shown).
In one embodiment, the intermediate transfer medium 20 includes a release layer between the second substrate 21 and the receiving layer 22 (not shown). When the intermediate transfer medium 20 includes a release layer and a release layer, the release layer and the release layer are provided in this order between the second base material 21 and the receiving layer 22.
In one embodiment, the intermediate transfer medium 20 includes a protective layer between the second substrate 21 and the receiving layer 22 (not shown). When the intermediate transfer medium 20 includes a release layer and a protective layer, the release layer and the protective layer are provided in this order between the second base material 21 and the receiving layer 22.
Hereinafter, each layer included in the intermediate transfer medium constituting the combination of the present disclosure will be described. Since the thermal transfer sheet has been described above, the description thereof is omitted here. Further, the release layer and the release layer that can be provided in the intermediate transfer medium are the same as those in the release layer and the release layer provided in the thermal transfer sheet, and thus the description thereof will be omitted here.

(Intermediate transfer medium)
(Second base material)
As the second base material, a material that can be used for the first base material can be appropriately selected and used.

The thickness of the second base material is, for example, 1 μm or more and 50 μm or less.

(Receptive layer)
In one embodiment, the receiving layer comprises at least one resin material. For example, vinyl resins such as polyolefins, polyvinyl chlorides and vinyl chloride-vinyl acetate copolymers, (meth) acrylic resins, cellulose resins, polyesters, polyamides, polycarbonates, styrene resins, epoxy resins, polyurethanes, epoxy resins and ionomer resins and the like. Can be mentioned.
Among these, a vinyl resin is preferable, and a vinyl chloride-vinyl acetate copolymer is particularly preferable, from the viewpoint of adhesion to the melt transfer type colored layer and acceptability of the sublimation dye.

The content of the resin material in the receiving layer is preferably 80% by mass or more and 99.5% by mass or less, and more preferably 85% by mass or more and 99% by mass or less. Thereby, the adhesion to the melt transfer type colored layer and the acceptability of the sublimation dye can be further improved.

The receiving layer may contain the above-mentioned mold release material and additive material.

The thickness of the receiving layer is preferably 0.5 μm or more and 20 μm or less, and more preferably 1 μm or more and 10 μm or less.

In the receiving layer, the material is dispersed in water or a suitable solvent, or the material is dissolved in water or a suitable solvent to prepare a coating liquid, which is applied onto the second substrate by the coating means. To form a coating film, which can be dried.

(Protective layer)
The protective layer contains at least one resin material. For example, polyester, (meth) acrylic resin, epoxy resin, styrene resin, acrylic polyol resin, polyurethane, active photocurable resin and the like can be mentioned.
In the present disclosure, the "active photocurable resin" means a resin in a state in which the active photocurable resin is irradiated with active rays and cured.
Further, in the present disclosure, the "active ray" means a radiation that chemically acts on an active ray-curable resin to promote polymerization, and specifically, visible light, ultraviolet rays, X-rays, and electrons. It means line, α ray, β ray, γ ray, etc.

The protective layer may contain the above additives.

The thickness of the protective layer is preferably 0.5 μm or more and 7 μm or less, and more preferably 1 μm or more and 5 μm or less. Thereby, the durability of the protective layer can be further improved.

In the protective layer, the above-mentioned material is dispersed in water or a suitable solvent, or the above-mentioned material is dissolved in water or a suitable solvent to prepare a coating liquid, and the above-mentioned coating means is used on the second base material or the like. It can be formed by applying it to a coating film and drying it.

Next, the thermal transfer sheet of the present disclosure will be described in more detail with reference to Examples, but the thermal transfer sheet of the present disclosure is not limited to these Examples.

Example 1
[Preparation of thermal transfer sheet]
A release layer forming coating solution having the following composition was applied and dried on one surface of a 4.5 μm-thick PET film to form a 0.8 μm-thick release layer.
<Coating liquid for mold release layer formation>
・ High Tg urethane resin A 7 parts by mass (Tg 92 ° C)
-Low Tg urethane resin B 23 parts by mass (Tg-30 ° C)
-70 parts by mass of acetal resin (manufactured by Sekisui Chemical Co., Ltd., Eslek (registered trademark) KS-5, Tg 110 ° C)
-Toluene 950 parts by mass-Methyl ethyl ketone (MEK) 950 parts by mass

A coating liquid for forming a release layer having the following composition was applied and dried on the release layer to form a release layer having a thickness of 1 μm.
<Coating liquid for forming a release layer>
-Vinyl chloride-vinyl acetate copolymer 85 parts by mass (manufactured by Nissin Chemical Industry Co., Ltd., Solveine (registered trademark) CNL)
・ (Meta) acrylic resin 15 parts by mass (manufactured by Shin Nakamura Chemical Industry Co., Ltd., vana resin GH-8701)
-Epoxy modified silicone oil 2 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., KP-1800U)
・ 150 parts by mass of toluene ・ 150 parts by mass of MEK

A coating liquid for forming a melt transfer type color material layer having the following composition was applied and dried on the release layer to form a melt transfer type color material layer having a thickness of 1.5 μm. In this embodiment, the release layer and the melt transfer type color material layer correspond to the transfer layer.
<Coating liquid for forming a melt transfer type color material layer>
・ 40 parts by mass of carbon black ・ 60 parts by mass of vinyl chloride-vinyl acetate copolymer ・ 100 parts by mass of toluene

A coating liquid for forming a back layer having the following composition was applied to the other surface of the PET film and dried to form a back layer having a thickness of 1 μm to obtain a thermal transfer sheet.
<Coating liquid for forming the back layer>
20 parts by mass of polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., Eslek (registered trademark) BX-1)
44 parts by mass of isocyanate compound (manufactured by DIC Corporation, Burnock (registered trademark) D750)
・ Surfactant 13 parts by mass (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Prysurf (registered trademark) A208N)
・ 3 parts by mass of talc (manufactured by Nippon Talc Co., Ltd., Micro Ace (registered trademark) P-3, average particle size 5 μm)
・ Toluene 460 parts by mass ・ MEK 460 parts by mass

[Preparation of intermediate transfer medium]
As a second base material, a PET film having a thickness of 12 μm was prepared. A coating liquid for forming a release layer having the following composition was applied to one surface of the PET film and dried to form a release layer having a thickness of 1 μm.
<Coating liquid for forming a release layer>
-(Meta) acrylic resin 95 parts by mass (manufactured by Mitsubishi Chemical Corporation, Dianal (registered trademark) BR-87)
・ 5 parts by mass of polyester (manufactured by Toyobo Co., Ltd., Byron (registered trademark) 200)
・ 200 parts by mass of toluene ・ 200 parts by mass of MEK

On the release layer, a coating liquid for forming a protective layer having the following composition was applied and dried to form a protective layer having a thickness of 1.5 μm.
<Coating liquid for forming a protective layer>
20 parts by mass of polyester (manufactured by Unitika Ltd., Elitel (registered trademark) UE-9885)
・ 40 parts by mass of toluene ・ 40 parts by mass of MEK

A coating liquid for forming a receiving layer having the following composition was applied onto the protective layer and dried to form a receiving layer having a thickness of 1.5 μm to obtain an intermediate transfer medium.
<Coating liquid for forming a receptive layer>
-95 parts by mass of vinyl chloride-vinyl acetate copolymer (Solvine (registered trademark) CNL manufactured by Nisshin Kagaku Kogyo Co., Ltd.)
・ Epoxy modified silicone oil 5 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., KP-1800U)
・ 200 parts by mass of toluene ・ 200 parts by mass of MEK

Examples 2 to 7 and Comparative Examples 1 to 4
A thermal transfer sheet was prepared in the same manner as in Example 1 except that the composition of the release layer was changed as shown in Table 1.

<< Measurement of peeling force during heat >>
The melt transfer type color material layer surface of the thermal transfer sheet obtained in Examples and Comparative Examples and a polyvinyl chloride (PVC) card (manufactured by Dai Nippon Printing Co., Ltd., width 50 mm × length 70 mm) as a transfer body were used. The sheets were opposed to each other and printed using the following test printer to obtain a laminated body in which the thermal transfer sheet and the transferred body were in close contact with each other.
(Test printer)
-Thermal head: Kyocera Corporation, KEE-57-12GAN2-STA
-Average resistance value of heating element: 3303Ω
-Main scanning direction resolution: 300 dpi (dot per inch)
-Sub-scanning direction resolution: 300 dpi
・ Printing voltage: 18V
-Line speed: 2.0 msec. / Line
-Printing start temperature: 35 ° C
-Pulse duty ratio: 85%
-Print image: Solid black image (0/255 image gradation)

The laminate was cut into a width of 25 mm to prepare a peeling force measurement sample having a width of 25 mm and a length of 70 mm. A peeling tester (VPA-3 manufactured by Kyowa Interface Science Co., Ltd.) was prepared, and the above-mentioned peeling force measurement sample was placed on the stage provided in the peeling tester so that the transferee side was in contact with the stage. The peeling tester was set as follows and allowed to stand for 3 minutes.
Next, the base material of the thermal transfer sheet was peeled off, and the peeling force was measured. The peeling interface was between the release layer and the peeling layer.
(Peeling tester conditions)
・ Stage temperature: 60 ° C
・ Peeling angle: 90 °
・ Peeling speed: 2000 mm / min

<< Evaluation of reverse transcription inhibitory >>
The thermal transfer sheet obtained in Examples and Comparative Examples, an intermediate transfer medium prepared as described below, and a printer (manufactured by Canon Finetech Nisca Inc., PR-C201) were prepared.
Using the above printer, the transfer layer of the thermal transfer sheet was transferred onto the receiving layer provided in the intermediate transfer medium to form the pattern image A (line thickness 2 dots) shown in FIG. The image was formed in an environment of 10 ° C. and a relative humidity of 30%. Further, FIG. 6 shows a partially enlarged version of the pattern image.
The image-formed intermediate transfer medium was visually observed and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
A: No peeling of the receptive layer was observed, and high reverse transcription inhibitory property was confirmed.
NG: The receptive layer was peeled off.

<< Transcription Evaluation-1 >>
The thermal transfer sheet, the intermediate transfer medium, the PVC card and the printer obtained in Examples and Comparative Examples were prepared.
Using the above printer, the transfer layer of the thermal transfer sheet was transferred onto the receiving layer provided in the intermediate transfer medium to form the pattern image A. The image was formed in an environment of 20 ° C. and a relative humidity of 50%.
After image formation, the receiving layer and the peeling layer of the intermediate transfer medium were transferred onto a PVC card to produce a printed matter.
The obtained printed matter was visually observed and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
A: No blurring was observed in the formed image.
B: A slight blurring was observed in the formed image, but there was no problem in practical use.
NG: Occurrence of blurring was observed in the formed image, and there was a problem in practical use.

<< Transcription Evaluation-2 >>
The printed matter obtained in the above transferability evaluation-1 was visually observed and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
A: No blurring was observed in the formed image.
B: A slight blurring was observed in the formed image, but there was no problem in practical use.
NG: Occurrence of blurring was observed in the formed image, and there was a problem in practical use.

Hereinafter, an embodiment of the heat transfer sheet of the present disclosure and a combination of the heat transfer sheet and the intermediate transfer medium will be illustrated. The thermal transfer sheet and the combination of the thermal transfer sheet and the intermediate transfer medium of the present disclosure are not limited thereto.

The thermal transfer sheet of the present disclosure includes a first base material, a release layer, and a transfer layer including at least a melt transfer type color material layer.
The 25 mm wide release layer contains at least two urethane resins and at least one acetal resin.
The thermal peeling force of the transfer layer is 0.4 N or more and 0.8 N or less.

In one embodiment, the release layer comprises a high Tg urethane resin and a low Tg urethane resin.
The glass transition temperature of the high Tg urethane resin is 50 ° C. or higher, and the glass transition temperature of the low Tg urethane resin is 10 ° C. or lower.

In one embodiment, the content ratio of the high Tg urethane resin and the low Tg urethane resin (high Tg urethane resin / low Tg urethane resin) in the release layer is 5/30 or more and 30/5 or less on a mass basis.

In one embodiment, the content of the high Tg urethane resin in the release layer is 5% by mass or more and 35% by mass or less.

In one embodiment, the content of the low Tg urethane resin in the release layer is 3% by mass or more and 35% by mass or less.

In one embodiment, the glass transition temperature of the acetal resin in the release layer is 60 ° C. or higher and 120 ° C. or lower.

In one embodiment, the content of the acetal resin in the release layer is 55% by mass or more and 90% by mass or less.

In one embodiment, the thickness of the release layer is 0.1 μm or more and 5 μm or less.

In one embodiment, the transfer layer includes a release layer under the melt transfer type color material layer.

In one embodiment, the release layer comprises a (meth) acrylic resin and a vinyl resin.

In one embodiment, the release layer comprises a mold release material.

In one embodiment, the content of the release material in the release layer is 0.1% by mass or more and 20% by mass or less.

The combination of the thermal transfer sheet and the intermediate transfer medium of the present disclosure includes the thermal transfer sheet, an intermediate transfer medium including the second base material, and a receiving layer.

10: Thermal transfer sheet, 11: First substrate, 12: Release layer, 13: Transfer layer, 14: Melt transfer type color material layer, 15: Release layer, 16: Sublimation transfer type color material layer, 17: Back layer , 20: Intermediate transfer medium, 21: Second substrate, 22: Receptive layer

Claims (13)

A first base material, a release layer, and a transfer layer including at least a melt transfer type color material layer are provided.
The release layer contains at least two types of urethane resin and at least one type of acetal resin.
A thermal transfer sheet having a 25 mm wide transfer layer having a thermal peeling force of 0.4 N or more and 0.8 N or less. The release layer contains a high Tg urethane resin and a low Tg urethane resin.
The glass transition temperature of the high Tg urethane resin is 50 ° C. or higher.
The thermal transfer sheet according to claim 1, wherein the glass transition temperature of the low Tg urethane resin is 10 ° C. or lower. The claim that the content ratio (high Tg urethane resin / low Tg urethane resin) of the high Tg urethane resin and the low Tg urethane resin in the release layer is 5/30 or more and 30/5 or less on a mass basis. 2. The thermal transfer sheet according to 2. The thermal transfer sheet according to claim 2 or 3, wherein the content of the high Tg urethane resin in the release layer is 5% by mass or more and 35% by mass or less. The thermal transfer sheet according to any one of claims 2 to 4, wherein the content of the low Tg urethane resin in the release layer is 3% by mass or more and 35% by mass or less. The thermal transfer sheet according to any one of claims 1 to 5, wherein the glass transition temperature of the acetal resin in the release layer is 60 ° C. or higher and 120 ° C. or lower. The thermal transfer sheet according to any one of claims 1 to 6, wherein the content of the acetal resin in the release layer is 55% by mass or more and 90% by mass or less. The thermal transfer sheet according to any one of claims 1 to 7, wherein the release layer has a thickness of 0.1 μm or more and 5 μm or less. The thermal transfer sheet according to any one of claims 1 to 8, wherein the transfer layer includes a release layer under a melt transfer type color material layer. The thermal transfer sheet according to claim 9, wherein the release layer contains a (meth) acrylic resin and a vinyl resin. The thermal transfer sheet according to claim 9 or 10, wherein the release layer contains a release material. The thermal transfer sheet according to any one of claims 9 to 11, wherein the content of the release material in the release layer is 0.1% by mass or more and 20% by mass or less. A combination of the thermal transfer sheet according to any one of claims 1 to 12 and an intermediate transfer medium.
A combination of a thermal transfer sheet and an intermediate transfer medium, wherein the intermediate transfer medium comprises a second substrate and a receiving layer.

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